Bulldozer lift cylinder arrangement

ABSTRACT

A tractor has a bulldozer assembly pivotally fitted thereto. A cylinder extends upwardly from the bulldozer assembly, and second and third cylinders extend upwardly from a forwardly extending frame portion of the tractor. A yoke interconnects the upper ends of the three cylinders adjacent the nose portion of the tractor. Restraining bell cranks interconnect the nose portion and the yoke. The cylinders are substantially vertically disposed, so that vertical loads on the bulldozer assembly are carried substantially fully by the first cylinder, and transferred through the yoke to the second and third cylinders to the forwardly extending frame portion, with minimal loading being carried by the restraining bell cranks.

United States Patent [1 1 [111 3,800,885

Gianessi 1 Apr. 2, 1974 BULLDOZER LIFT CYLINDER Primary ExaminerStephen C. Pellegrino ARRANGEMENT Attorney, Agent, or Firm-Fryer, Tjensvold, Phillips & Lempio [57] ABSTRACT A tractor has a bulldozer assembly pivotally fitted thereto. A cylinder extends upwardly from the bulldozer assembly, and second and third cylinders extend upwardly from a forwardly extending frame portion of the tractor. A yoke interconnects the upper ends of the three cylinders adjacent the nose portion of the tractor. Restraining bell cranks interconnect the nose portion and the yoke. The cylinders are substantially vertically disposed, so that vertical loads on the bulldozer assembly are carried substantially fully by the first cylinder, and transferred through the yoke to the second and third cylinders to the forwardly extending frame portion, with minimal loading being carried by the restraining bell cranks.

5 Claims, 3 Drawing Figures BULLDOZER LIFT CYLINDER ARRANGEMENT BACKGROUND OF THE INVENTION This invention relates to a bulldozer blade lift cylinder arrangement, and more particularly, to such an arrangement which transmits substantially all vertical loading on the blade to the frame of the tractor involved.

In prior art vehicles incorporating a tractor and a bulldozer assembly including push arms and a bulldozer blade, the bulldozer blade thereof is generally raised and lowered by lift cylinders attached to the bulldozer assembly and to a radiator guard disposed at the forward end of the vehicle. (See, for example, U.S. Pat. No. 3,441,091 to Helling, U.S. Pat. No. 3,386,519 to Long, and U.S. Pat. No. 3,279,105 to Kolinger et al.). Due to the very great vertical loading applied to the blade under some conditions, the prior art radiator guards to which such vertical load is transferred have had to be extremely strong and heavy to properly carry such load. Such construction substantially contributes to the expense of the radiator guard and also imposes space restrictions on the various heat exchanger and engine cooling fan components normally associated therewith, and further contributes to additional servicing difficulties in connection with the cooling system and engine.

In addition, in order to obtain the full range of bulldozer blade lifting required, such extendible cylinders have been heretofore of substantial length. Such increased cylinder length not only adds to the manufacturing expense of the lifting mechanism, but also may contribute to poor visibility in that they may for example extend over the hoodline of the vehicle.

Of more general interest in this area are U.S. Pat. No. 3,565,181 to Bahm et al., U.S. Pat. No. 3,161,072 to Le Tourneau, U.S. Pat. No. 3,142,197 to Le Tourneau, and U.S. Pat. No. 3,222,804 to Kuhl.

SUMMARY OF THE INVENTION It is an object of this invention to provide a lift cylinder arrangement in a bulldozer vehicle which transfers substantially all the vertical loading on the bulldozer assembly thereof to the frame of the tractor involved.

It is a further object of this invention to provide a lift cylinder arrangement in a bulldozer which, while fulfilling the above object, allows relatively unobstructed operator vision in its use.

It is a still further object of this invention to provide a lift cylinder arrangement in a bulldozer which is extremely simple and economical in design and effective in operation.

Broadly stated, the invention is a vehicle assembly comprising a tractor having a frame including a forwardly extending frame portion and a nose portion. Further included is a bulldozer assembly comprising a pair of forwardly extending push arms disposed on either side of the tractor and pivotally connected relative to the tractor frame, and a blade connected to the forward end of the push arms, the push arms being pivotable to raise and lower the blade adjacent the nose portion of the tractor. An elongated member is connected to and extends upwardly from the forwardly extending frame portion in a generally vertical attitude. An extendible and retractable cylinder is connected to and extends upwardly from the bulldozer assembly in a generally vertical attitude. Rigid means interconnect the upper ends of the elongated member and cylinder to limit relative movement between said upper ends. Restraining means interconnect the nose portion of the tractor with one of the rigid means, upper end of the elongated member, and upper end of the cylinder, so that vertical loading on the blade is substantially fully carried by the cylinder and transferred from the cylinder through the rigid means to the elongated member and forwardly extending frame portion, with minimum vertical loading being transferred through the restraining means to said nose portion of the tractor, and so that horizontal loading on the blade is substantially fully carried by the push arms.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects of the invention will become apparent from a study of the following specification and drawings, in which:

FIG. 1 is a side elevation of a tractor incorporating the inventive system in combination with a bulldozer assembly;

FIG. 2 is a front elevation of the tractor of FIG. 1, with the bulldozer assembly in a lowered position; and,

FIG. 3 is a view similar to that of FIG. 2 but with the bulldozer assembly in its fully raised position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Shown generally in FIG. 1 is a vehicle assembly 10 including a track-type, earthmoving tractor 12. Such tractor 12 has a frame 14 having a main frame portion 16. Such frame 14 includes a pair of conventional, laterally spaced, parallel undercarriage frames 20 individually disposed on either side. Such tractor 12 includes an operator station 22 and an engine compartment 24. Further included is a bulldozer assembly 26 made up of a pair of forwardly extending push arms 28, 30 disposed on either side of the tractor 12 and pivotally connected to the undercarriage frames 20 by pivotal connections 32', and a blade 34 connected to the forward ends of the push arms 28, 30. Inte'rconnecting the push arms 28, 30 and blade 34 are extendible and retractable brace mechanisms 36, each having its opposite ends pivotally fixed to a push arm and the blade 34, and through which the attitude or angularity of the blade 34 may be varied.

The main frame portion 16 includes a pair of forwardly extending frame portions 38, 40, and a cross member 42 rigidly secured thereto below the engine compartment 24. A radiator guard 44, defining the nose portion of the tractor 12, is removably secured to the forwardly extending frame portions 38, 40 and the cross member 42.

The forwardly extending frame portions 38, 40 include respective brackets 45, 46. Extendible and retractable cylinders 48, 50 are pivotally secured to brackets 45, 46 by transverse pivot pins 52, 54, and extend upwardly therefrom. An extendible and retractable cylinder 56 is pivotally connected to blade 34 by means of a transverse pin 57 and extends upwardly from the blade 34. The cylinders 48, 50 have their upper ends pivotally fixed to a yoke 58, by means of transverse pins 59, 61, and the cylinder 56 has its upper end pivotally fixed to the yoke 58 also. Restraining members 62, 64 are pivotally fixed relative to the nose portion 44', actually being pivotally fixed by transverse pins to brackets 66, 68 which pass through suitable openings in the engine hood 70 and are suitably mounted to framing of and within the nose portion 44.

The restraining members 62, 64 extend generally forwardly of the nose portion 44, and the yoke 58 is pivotally fixed to the forwardly extending ends of said restraining members 62, 64 by means of transverse pins 59, 61.

The yoke 58 is disposed generally transversely of the tractor 12, and acts as rigid bar means interconnecting the upper ends of the cylinders 48, 50, 56 to limit relative movement between these upper ends.

In such situation, it is to be noted that cylinders 48, 50, 56 are each disposed in a generally vertical attitude. The cylinders 48, 50 are disposed substantially parallel to each other, and are disposed on either side of the cylinder 56, with the cylinder 56 substantially midway between the cylinders 48,50.

FIGS. 1 and 2 show the normal operating condition wherein the cylinders 48,50 are substantially retracted and the cylinder 56 is extendible and retractable to pivot the push arms 28,30 to raise and lower the blade 34 adjacent the radiator guard 44 of the tractor 12. In order to extend the lifting height of the blade 34, it is necessary to retract the cylinder 56 and then to extend the cylinders 48 and 50 to the maximum raised position shown in phantom in FIG. 1, and also shown in the front view of FIG. 3. Thus, extension of cylinders 48,50 moves the yoke 58 to raise the cylinder 56 and blade 34 together, and retracting of the cylinders 48,50 moves the yoke 58 to lower the cylinder 56 and blade 34 together. FIG. 1 shows that the total range movement of the cylinders longitudinally of the vehicle is minimal. This allows very close positioning of the blade 34 to the nose portion 44 of the tractor l2, and improved blade handling of the material.

The vertical loads imposed on the bulldozer blade 34 are substantially fully carried by the cylinder 56 and transferred therefrom through the yoke 58 to the cylinders 48 and 50, and to the forwardly extending frame portions 38,40. The horizontal loads on the blade 34 are of course carried substantially fully by the push arms 28,30. Since the restraining members 62, 64 are used primarily for positioning purposes and transmit only minimal vertical loading, the radiator guard 44 can be of lighter, more economical construction than prior art guards which must withstand large loads. Further, the lighter radiator guard '44 can be removed more easily to provide access to other engine-related components rearwardly thereof.

In addition to the advantage of frame-mounted cylinders 48, 50, the length of the cylinders 48, 50 can be shorter, and so will not require as large a diameter rod as a longer cylinder would. This results in manufacturing economies.

The cylinder 56 is preferably the working" cylinder for the majority of ground-level work. By using such a center-mounted cylinder 56 instead of two laterally spaced lift cylinders, blade corner loading which would normally be transmitted to one side of the tractor frame will be substantially eliminated, reducing frame twistmg.

In connection with visibility, it should be noted that the yoke 58 and restraining members 62, 64 do not detract from visibility in the normal operating mode shown in solid lines in FIG. 1 and 2. Even with the blade 34 raised to its maximum height, as shown in FIG. 3, operator visibility is entirely satisfactory. Thus, the low-profile, high-lift cylinder arrangement of the subject invention, along with the direct frame mounting thereof, is a substantial improvement in the art.

What is claimed is:

1. A vehicle assembly comprising:

a tractor having a frame including a forwardly extending frame portion and a nose portion;

a bulldozer assembly comprising a pair of forwardly extending push arms disposed on either side of the tractor and pivotally connected relative to the tractor frame and a blade connected to the forward ends of the push arms the push arms being pivotable to raise and lower the blade adjacent the nose portion of the tractor;

an elongated member connected to and extending upwardly from the forwardly extending frame portion in a generally vertical attitude;

an extendible and retractable cylinder pivotally connected to and extending upwardly from the bulldozer assembly in a generally vertical attitude;

rigid means interconnecting the upper ends of the elongated member and cylinder to limit relative movement between said upper ends, the rigid means being pivotally connected to one of the upper end of the elongated member and the upper end of the cylinder; and,

restraining means interconnecting the nose portion of the tractor with one of the rigid means, upper end of the elongated member, and upper end of the cylinder, so that vertical loading on the blade is substantially fully carried by the cylinder and transferred from the cylinder to the rigid means to the elongated member and forwardly extending frame portion, with minimal vertical loading being transferred through the restraining means to said nose portion of the tractor, and so that horizontal loading on the blade is substantially carried by the push arms.

2. The vehicle assembly of claim 1 wherein the rigid means comprise a yoke comprising a rigid bar interconnecting the upper ends of the elongated member and cylinder and pivotally attached thereto, and the restraining means comprise a restraining member pivotally connected to the rigid bar and extending therefrom and pivotally fixed relative to said nose portion, and wherein the elongated member comprises a second extendible and retractable cylinder, pivotally fixed to the forwardly extending frame portion, the extension of which moves the yoke to raise the first cylinder and blade together, and the retraction of which moves the yoke to lower the first cylinder and blade together.

3. A vehicle assembly comprising:

a tractor having a frame including a forwardly extending frame portion and a nose portion;

a bulldozer assembly comprising a pair of forwardly extending push arms disposed on either side of the tractor and pivotally connected relative to the tractor frame, and a blade connected to the forward ends of the push arms, the push arms being pivotable to raise and lower the blade adjacent the nose portion of the tractor;

first and second restraining members pivotally fixed relative to the nose portion and extending generally forwardly thereof;

a yoke pivotally fixed to the forwardly extending ends of the first and second restraining members and disposed generally transversely of the tractor;

a first extendible and retractable cylinder extending upwardly from the bulldozer assembly in a generally vertical attitude and pivotally fixed at its upper end to the yoke;

second and third extendible and retractable cylinders pivotally connected to and extending upwardly from the forwardly extending frame portion in a generally vertical attitude and pivotally fixed at their upper ends to the yoke, so that vertical loading on the blade is substantially fully carried by the first cylinder and transferred from the first cylinder through the yoke to the second and third cylinders and forwardly extending frame portion, with minimum vertical loading being transferred through the restraining member to said nose portion of the tractor, and so that horizontal loading on the blade is substantially fully carried by the push arms;

the extension of the second and third cylinders raising the yoke to raise the first cylinder and blade together, and the retraction of the second and third cylinders lowering the yoke to lower the first cylinder and blade together.

4. The vehicle assembly of claim 3 wherein the second and third cylinders are substantially parallel and are disposed on either side of the first cylinder, with the first cylinder substantially midway between the second and third cylinders.

5. The vehicle assembly of claim 4 wherein the blade is pivotally connected to the forward ends of the push arms, and further comprising additional extendible and retractable means interconnecting the push arms and blade for varying the attitude of the blade. 

1. A vehicle assembly comprising: a tractor having a frame including a forwardly extending frame portion and a nose portion; a bulldozer assembly comprising a pair of forwardly extending push arms disposed on either side of the tractor and pivotally connected relative to the tractor frame and a blade connected to the forward ends of the push arms the push arms being pivotable to raise and lower the blade adjacent the nose portion of the tractor; an elongated member connected to and extending upwardly from the forwardly extending frame portion in a generally vertical attitude; an extendible and retractable cylinder pivotally connected to and extending upwardly from the bulldozer assembly in a generally vertical attitude; rigid means interconnecting the upper ends of the elongated member and cylinder to limit relative movement between said upper ends, the rigid means being pivotally connected to one of the upper end of the elongated member and the upper end of the cylinder; and, restraining means interconnecting the nose portion of the tractor with one of the rigid means, upper end of the elongated member, and upper end of the cylinder, so that vertical loading on the blade is substantially fully carried by the cylinder and transferred from the cylinder to the rigid means to the elongated member and forwardly extending frame portion, with minimal vertical loading being transferred through the restraining means to said nose portion of the tractor, and so that horizontal loading on the blade is substantially carried by the push arms.
 2. The vehicle assembly of claim 1 wherein the rigid means comprise a yoke comprising a rigid bar interconnecting the upper ends of the elongated member and cylinder and pivotally attached thereto, and the restraining means comprise a restraining member pivotally connected to the rigid bar and extending therefrom and pivotally fixed relative to said nose portion, and wherein the elongated member comprises a second extendible and retractable cylinder, pivotally fixed to the forwardly extending frame portion, the extension of which moves the yoke to raise the first cylinder and blade together, and the retraction of which moves the yoke to lower the first cylinder and blade together.
 3. A vehicle assembly comprising: a tractor having a frame including a forwardly extending frame portion and a nose portion; a bulldozer assembly comprising a pair of forwardly extending push arms disposed on either side of the tractor and pivotally connected relative to the tractor frame, and a blade connected to the forward ends of the push arms, the push arms being pivotable to raise and lower the blade adjacent the nose portion of the tractor; first and second restraining members pivotally fixed relative to the nose portion and extending generally forwardly thereof; a yoke pivotally fixed to the forwardly extending ends of the first and second restraining members and disposed generally transversely of the tractor; a first extendible and retractable cylinder extending upwardly from the bulldozer assembly in a generally vertical attitude and pivotally fixed at its upper end to the yoke; second and third extendible and retractable cylinders pivotally connected to and extending upwardly from the forwardly extending frame portion in a generally vertical attitude and pivotally fixed at their upper ends to the yoke, so that vertical loading on the blade is substantially fully carried by the first cylinder and transferred from the first cylinder through the yoke to the second and third cylinders and forwardly extending frame portion, with minimum vertical loading being transferred through the restraining member to said nose portion of the tractor, and so that horizontal loading on the blade is substantially fully carried by the push arms; the extension of the second and third cylinders raising the yoke to raise the first cylinder and blade together, and the retraction of the second and third cylinders lowering the yoke to lower the first cylinder and blade together.
 4. The vehicle assembly of claim 3 wherein the second and third cylinders are substantially parallel and are disposed on either side of the first cylinder, with the first cylinder substantially midway between the second and third cylinders.
 5. The vehicle assembly of claim 4 wherein the blade is pivotally connected to the forward ends of the push arms, and further comprising additional extendible and retractable means interconnecting the push arms and blade for varying the attitude of the blade. 